Existing machines for terminating the ends of electrical windings of bobbins must be able to accommodate different styles and types of terminals. In all cases the terminal is severed from the carrier strip by a cutting blade and then it is inserted into a terminal receiving cavity of the bobbin. During insertion, the cutting blade remains extended to guide the loose terminal. The depth of insertion is controlled by means of an adjustable stop, usually a screw having a lock nut for locking it in place once the adjustment is complete. The screw may either be threaded into the movable insertion carriage and abut against the machine frame or be threaded into the frame and abut against the movable carriage. Such an adjusting mechanism is usually satisfactory for controlling the depth of insertion to within about 0.010 inch. However, due to the trend toward smaller, high density equipment, the positioning of components becomes more critical. Such is the case with certain wire wound bobbins where the depth of insertion of the terminals must be controlled to within about 0.001 to 0.002 inch. In these situations the traditional stop screw is ineffective. What is needed is a fine adjusting mechanism that works in cooperation with the stop screw to allow very precise depth adjustments.